ARTIFICIAL PARTHENOGENESIS IN THE SILKWORM. \J 



of calcium chloride and then of concentrated sulphuric acid), 

 high temperature, sunlight, friction, sulphuric acid, hydrochloric 

 acid, glacial phosphoric acid, glacial acetic acid, absolute alcohol, 

 potassium hydroxide, ammonia, and lime water. The reagents 

 were used in different dilutions and for varying lengths of time. 

 The treatment was applied to eggs not more than twelve hours 

 old ; mostly to eggs but a few minutes to a few hours old. Five 

 hundred or more lots of untreated, unfertilized eggs were 

 observed in order to determine the extent of normal parthenoge- 

 netic development. The eggs of half a dozen silkworm races were 

 used and all the eggs were preserved from time of laying until 

 their death. 



As it seemed to me that most of the favorable results obtained 

 by Tichomiroff and Quajat were obtained by treatments which had 

 as common effect a dehydration (such as high temperature, fric- 

 tion, sulphuric acid, etc.) I attempted to test this first by using 

 various dehydrating agents, especially a dry chamber in which 

 the eggs could be submitted for from a minute or two to several 

 hours to a nearly perfectly dry atmosphere. Friction, heat, sul- 

 phuric acid, phosphoric pentoxide and glacial phosphoric acid were 

 also used as dehydrating agents. At the same time other treat- 

 ment, not dehydrating, was used on other lots and gave results 

 hardly less favorable than the dehydrating. The results at the end 

 of this first course of treatment seemed to point to the hydrogen 

 ions as the most likely development-inciting factor. Hence va- 

 rious agents agreeing in containing hydrogen ions though differ- 

 ing radically in other particulars were used. The results gave no 

 encouragement to the hydrogen ion theory. In fact I have not 

 been able to come to an opinion concerning the true causa efficiens 

 in the matter. My results simply show to me that various 

 stimuli, acid or alkaline, dehydrating or non-dehydrating, posses- 

 sing or not possessing hydrogen ions, are able to increase mate- 

 rially the proportion of eggs that develop in lots of unfertilized 

 eggs. The following paragraphs give baldly a summary of the 

 results obtained. 



Treatment of Unfertilized Eggs by Dry Air. — Freshly depos- 

 ited eggs placed in dry chamber for from 14 minutes to 2 hours. 

 Ten lots of unfertilized eggs. In all these lots, except one, a 



